Occidental Petroleum Corp.’s third-quarter profit fell 24% as oil prices slumped, offering a preview of how other international oil companies will be affected by cheaper crude.

The Houston-based company on Thursday reported a $1.2 billion profit as oil prices fell 9% from a year earlier and expenses rose for tapping oil and natural gas. Crude prices have dropped more steeply in recent months and are likely to mean lower profit for Chevron Corp., Exxon Mobil Corp. and other major oil producers that report earnings next week.